The Short Answer Educational content only. Any suspected concussion warrants medical evaluation. Persistent sensory symptoms after concussion warrant assessment by the appropriate specialist, an audiologist or ENT for hearing and sound symptoms, a neuro-optometrist or ophthalmologist for visual and eye symptoms, and a physician or neurologist to coordinate care. Consult a concussion-experienced clinician for individualized care. Parosmia develops after concussion when olfactory nerve fibers, damaged in the injury, regrow and reconnect incorrectly, so smells are distorted, often unpleasantly (Proskynitopoulos et al., 2016). Parosmia is a distortion of smell in which familiar odors smell wrong, frequently foul, rotten, chemical, or burnt. It typically follows a period of reduced or absent smell after head injury, appearing as the damaged olfactory system begins to regenerate. Because the regrowing nerve fibers reconnect imperfectly, the brain receives scrambled signals and interprets a known smell as something different and usually unpleasant. Parosmia is generally a sign of a recovering olfactory system rather than a new problem, and it often improves as the miswiring resolves. Smell training and strategies to keep eating tolerable support recovery. Parosmia is a distortion in which smells register as wrong, often foul. It arises when damaged olfactory fibers regrow and reconnect incorrectly. It usually signals regeneration and often improves over time. What Parosmia Is Parosmia is a qualitative distortion of smell: an odor is present and detected, but it smells wrong. A cup of coffee might smell like burning rubber, food like sewage or chemicals, and once-pleasant scents like rot or smoke. The distortions are typically unpleasant, which is what makes parosmia distressing, since everyday activities like eating and being around food become aversive. Parosmia is different from anosmia, the absence of smell, and from phantosmia, smelling something that is not there. In parosmia there is a real odor source, but the perception of it is corrupted. Parosmia after head injury usually emerges after an initial period of reduced or lost smell, as the olfactory system starts to recover. Its appearance, though unpleasant, is often a hopeful sign that regeneration is underway. How Miswiring Produces Distorted Smell The olfactory system encodes different smells through specific patterns of receptor and nerve fiber activation, and the brain learns to interpret these patterns as particular odors. When head trauma damages the olfactory nerve fibers and they later regenerate, the regrowing fibers do not always reconnect to their original targets. A fiber that once signaled one odor may reconnect in a way that activates a different pattern, so the brain receives a scrambled or mismatched signal for a familiar smell and interprets it incorrectly. This faulty rewiring during regeneration is what produces the distortion. The tendency for distortions to be unpleasant is thought to reflect how the disrupted patterns are interpreted, often triggering the brain's aversive and warning responses. As regeneration continues and connections refine, the wiring tends to become more accurate, which is why parosmia often improves over time. Why It Signals Recovery Although distressing, parosmia is generally an encouraging sign because it indicates that the olfactory system is regenerating. It appears when fibers that were damaged or absent begin to regrow and reconnect, even if imperfectly at first. A system with no regeneration would remain anosmic. The distorted smell means signals are once again reaching the brain, and as the connections mature and refine, the distortions commonly diminish and smell perception becomes more accurate. This is why parosmia is often framed as a stage in recovery rather than a setback, though the timeline is long and variable. Symptom Presentation Familiar smells registering as wrong, often foul, rotten, chemical, or burnt Coffee, food, and once-pleasant scents becoming aversive Onset after a period of reduced or absent smell Distortion of real odors rather than absence or phantom smells Aversion to eating and food environments Reduced appetite and food enjoyment Gradual improvement as regeneration continues Assessment An ENT specialist assesses parosmia by characterizing the distortions and confirming the pattern of olfactory recovery, often with formal smell testing that tracks change over time. The assessment distinguishes parosmia from phantosmia and confirms that a real odor source is being distorted rather than imagined. It places the parosmia in the context of the recovery timeline, since its appearance after anosmia signals regeneration. A physician coordinates care and monitors the extended course. Treatment Approach Smell training supports the refining of olfactory connections and can help parosmia as it does anosmia. Repeatedly and deliberately smelling a set of distinct scents over months gives the regenerating system consistent input to recalibrate against, which may speed the resolution of distortions. As with anosmia, consistency over a prolonged period matters, and earlier is generally better. Practical strategies keep eating tolerable while parosmia persists. Identifying and avoiding the specific trigger foods and smells that distort worst, favoring blander and cooler foods that release fewer aromas, and eating in ways that limit aroma reduce the aversion enough to maintain nutrition. Support for appetite and food enjoyment matters, since parosmia can make eating unpleasant. Reassurance that parosmia usually signals recovery and often improves helps with the distress. A physician monitors the long, variable course, and most people see the distortions ease as regeneration matures. Sensory symptoms after concussion improve faster when the nervous system is regulated and the neck and autonomic system are addressed alongside specialist care. Start your 3-day free trial to build a supportive daily routine. Supporting Mobility Routine JME 155 Diaphragmatic breathing lowers the sympathetic drive that amplifies sensory sensitivity and steadies the nervous system. Ten slow breaths, several times daily. JME 14 Chin tucks reduce upper cervical tension that feeds headache, dizziness, and sensory overload. Ten repetitions with 5-second holds. JME 1 Cervical rotation restores segmental mobility and supports blood flow through the vertebral arteries to the brain. Ten repetitions per direction. JME 15 Cervical lateral flexion addresses side-bending restriction that sustains neck tension and sensory strain. Ten repetitions per side. JME 16 Cervical flexion and extension restore sagittal mobility restricted by suboccipital guarding. Eight slow repetitions. JME 2 Cervical retraction reinforces a neutral head position that reduces the postural strain feeding sensory symptoms. Ten repetitions per set. JME 150 Thoracic rotation restores mid-back motion needed for full diaphragmatic breathing and relaxed upright posture. Eight repetitions per direction. JME 227 Overhead reach opens the thoracic spine and rib cage, supporting the deep breathing that calms an overloaded nervous system. Ten repetitions with controlled tempo. Start your 3-day free trial for joint-specific mobility programming that supports the nervous system regulation behind sensory recovery after concussion. Common Mistakes Treating parosmia as a setback rather than a sign of regeneration Abandoning smell training when distortions are unpleasant Letting food aversion reduce nutrition without adapting the diet Confusing parosmia with phantosmia, which differs in cause Expecting rapid resolution from a slow, months-long process Progression Assessment characterizes the distortions and places them in the recovery timeline, confirming regeneration. Smell training gives the refining system consistent input, while practical diet strategies keep eating tolerable and protect nutrition. Parosmia usually improves as olfactory connections mature over months, so the distortions ease and smell perception becomes more accurate. What is parosmia after a concussion? Parosmia is a distortion of smell in which familiar odors register as wrong, often foul, rotten, chemical, or burnt. A real odor source is present but perceived incorrectly. It typically appears after a period of reduced or absent smell as the damaged olfactory system regenerates and reconnects imperfectly. Why do things smell disgusting after my concussion? When damaged olfactory fibers regrow, they do not always reconnect to their original targets, so the brain receives scrambled signals for familiar smells and interprets them incorrectly, usually as something unpleasant. This faulty rewiring during regeneration produces the foul or chemical distortions, which tend to ease as connections refine. Is parosmia a good sign or a bad sign? Although distressing, parosmia is generally an encouraging sign, because it indicates the olfactory system is regenerating. It appears when damaged or absent fibers begin to regrow and reconnect, even if imperfectly. A system with no regeneration would stay anosmic, so the distorted smell means signals are reaching the brain again. Will parosmia go away after a concussion? It often improves as the regenerating olfactory connections mature and refine over months, so the distortions diminish and smell perception becomes more accurate. The timeline is long and variable, and recovery is not guaranteed, but many people see parosmia ease over time. Smell training may support the process. How can I keep eating with parosmia? Identify and avoid the specific foods and smells that distort worst, favor blander and cooler foods that release fewer aromas, and eat in ways that limit aroma. These reduce the aversion enough to maintain nutrition while parosmia persists. Support for appetite and food enjoyment helps, since parosmia can make eating unpleasant. Why Sensory Symptoms Happen After Concussion Sensory symptoms after concussion arise from disrupted sensory processing rather than damage to the sense organs alone. Concussion strains the connections between brain regions, alters the balance of excitation and inhibition, and leaves the nervous system in a sensitized, hyperexcitable state (Silverberg et al., 2020). In this state the brain turns up the gain on incoming signals, so ordinary light, sound, smell, taste, and touch are amplified, distorted, or perceived when absent. Some symptoms also reflect direct injury to sensory nerves. Most sensory symptoms improve over weeks to months as the brain recovers and the gain settles, and structured management speeds the process. Graded Exposure and Avoiding Overprotection A common trap in sensory recovery is total avoidance. Completely shielding from light, sound, or activity feels protective, but sustained avoidance makes the nervous system more sensitive over time, narrowing tolerance further. The better approach is graded exposure: staying within a tolerable range while gradually and deliberately increasing exposure as tolerance grows, never pushing far past the point where symptoms flare. This retrains the nervous system to accept normal sensory input. Extreme protection, such as constant dark glasses indoors or continuous earplug use, tends to worsen sensitivity and is used sparingly and strategically rather than continuously. Managing Sensory Overload Reduce competing sensory input by handling one channel at a time Take planned breaks in a calm, low-stimulation environment before overload builds Use diaphragmatic breathing to lower the arousal that amplifies sensitivity Pace demanding sensory environments rather than avoiding them entirely Protect sleep, since fatigue lowers sensory tolerance Treat coexisting headache, since pain and sensory sensitivity feed each other When to Seek Specialist Assessment Persistent or worsening sensory symptoms, symptoms that interfere with work or daily life, and any symptom with concerning features warrant specialist assessment. Hearing and sound symptoms are evaluated by an audiologist or ENT, who can test hearing and guide sound therapy. Visual and eye symptoms are evaluated by a neuro-optometrist or ophthalmologist. Smell and taste symptoms are evaluated by an ENT. A physician or neurologist coordinates care and excludes other causes. Pulsatile tinnitus, sudden vision or hearing loss, and rapidly worsening symptoms need prompt evaluation rather than watchful waiting. The Autonomic and Cervical Contribution Sensory symptoms rarely stand alone after concussion. Autonomic dysregulation keeps the nervous system in a heightened, sympathetic-dominant state that amplifies sensitivity, and cervical dysfunction feeds headache, dizziness, and sensory strain through shared brainstem pathways. Regulating the autonomic nervous system with diaphragmatic breathing and graded activity, and addressing the neck with mobility and manual therapy, lower the background arousal on which sensory symptoms ride. This is why calming the nervous system as a whole often eases sensory symptoms that specialist treatment alone does not fully resolve. References Proskynitopoulos, P. J., Stippler, M., & Kasper, E. M. (2016). Post-traumatic anosmia in patients with mild traumatic brain injury (mTBI): A systematic and illustrated review. Surgical Neurology International, 7(Suppl 15), S263-S275. PubMed Patricios, J. S., et al. (2023). Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport, Amsterdam, October 2022. British Journal of Sports Medicine, 57(11), 695-711. PubMed Silverberg, N. D., et al. (2020). Management of concussion and mild traumatic brain injury: a synthesis of practice guidelines. Archives of Physical Medicine and Rehabilitation, 101(2), 382-393. PubMed